Answer
$3{y^4} - 12{y^3} + 16{y^2} - 4y + 5$
Work Step by Step
$(3{y^2} + 1) ({y^2} - 4y +5)$
= $({y^2} -4y + 5)$
* $ (3{y^2} +1)$
= ${y^2} -4y +5$
+$3{y^4} - 12{y^3} + 15{y^2}$
=$ 3{y^4} - 12{y^3} + 15 {y^2} + {y^2} - 4y +5$
= $3{y^4} - 12{y^3} + 16{y^2} - 4y + 5$